Heretofore, vibration monitoring apparatus of this type included a computer wherein a vibration level detected by a vibration detector mounted on a rotary machine or the like is compared with an abnormal vibration level according to the rotational frequency of the rotary machine, and wherein an alarm is given when the vibration level exceeds the abnormal vibration level.
In vibration monitoring apparatus of this type, it is an important factor that the processing of vibration signals detected by a plurality of vibration detectors is performed at high precision and at high speed by a computer system.